Dead Power Supply Protek PUP110-40-S, Nicolet 6700 FTIR Spectrometer
stalled fan, two baked-out capacitors
SYMPTOM: increasing error messages "laser out of spec," "power supply out of tolerance," then full failure. On the supply module, no fan noise, and the +12VDC pin shows low.
Only two years and the fan has died of old age, causing two capacitors in the +12V section to slowly fail from from high-freq overheating.
Four screws found under adhesive foam disks. Replaced the dead Sunon NDE fan with NMB 60mm x 20mm 12VDC 100mA 06020SA-12M-AA00
C24 in the 12V regulation is providing filtered 16.5VDC to the TL431 reference chip. When failed, a large square wave appears there, with average voltage roughly 8VDC. Replace 47uF 35V capacitor. During the failure, the main +12VDC became a high-freq pulse waveform, which overheated the output filter C20, 1000uF 35V also replaced.
Internal wire colors
- BK BR OR - +5VDC
- RD VI GN - COM
- BU - -12VDC
- VI - +12VDC
- WH - -5VDC
- dk gn - case gnd and bottom foil shield
